ML081050298

NDE Report, on PSL-1, Pressurizer Nozzles, Attachment 1

ML081050298
Person / Time
Site:	Saint Lucie
Issue date:	03/19/2008
From:	John Ma Electric Power Research Institute
To:	King C Office of Nuclear Reactor Regulation
References
MRP 2008-027
Download: ML081050298 (170)

Text

Attachment 1 MRP 2008-012

Ma, Jennifer From: Ma, Jennifer Sent: Thursday, February 21, 2008 1:16 PM To: King, Christine

Subject:

Examination Results on Nozzles from removed St Lucie Pressurizer MRP 2008-012 Attachment.pdf (7...

February 21, 2008 MRP Letter 2008-012 (via email)

Dear MRP TAG Members:

In early 2007 as the NRC and industry were working to address questions regarding the possible existence of large circumferential indications in uninspected pressurizer nozzles, the potential knowledge to be gained from harvesting nozzles from either cancelled plants or retired pressurizers was studied carefully. Ultimately resolution of the immediate issues was accomplished without the direct evaluation of such nozzles but the EPRI NDE Center did acquire several nozzles from a cancelled plant and the NRC took custody of the nozzles from the St. Lucie 1 replaced pressurizer.

MRP has partnered with NRC Research in the initial evaluation of the St. Lucie nozzles by conducting dye penetrant (PT) exams of the nozzles (ID and OD) as well as phased array UT examinations. The phased-array UT examinations revealed multiple planar reflectors, which appear to be vertically stacked and extend from the ID surface to a significant through-wall depth in all three of the Safety nozzle DM welds. Under normal field NDE conditions these indications would likely be reported as 360° linear planar flaws. The approximate through-wall depths at the deepest points were 80% on the "A" Safety nozzle, 75% on the "B" Safety nozzle, and 69% on the "C" Safety nozzle. Additionally, one non-surface connected indication, indicative of lack of fusion was recorded on the Spray nozzle. No recordable indications were noted on the Relief or Surge nozzles, during the UT examinations.

MRP will work closely with NRC Research to define an appropriate plan for fully characterizing these indications. It is currently anticipated that additional NDE will be conducted, including the use of automated phased-array scans to more fully map the apparent flaws for comparison to any subsequent results from destructive analyses. These results will assist industry and NRC in refining the interpretation of NDE results from DM welds and in improving the understanding of the role of PWSCC in degradation of these materials.

The attached trip report provides further detail from these initial examinations and is provided for your information. As additional facts are developed, they will be communicated as well. If you have additional questions, please contact either Craig Harrington or Christine King.

Christine King Program Manager EPRI Materials Reliability Program Office: 650-855-2605 Mobile: 650-283-4235 cc: MRP IIG 1

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report St. Lucie Pressurizer DM weld examinations The scope of this project for EPRI was to oversee the examination of six dissimilar metal (DM) welds associated with the Combustion Engineering Pressurizer vessel that was recently removed from service from the St. Lucie Nuclear Power Station. The examinations were to include surface and volumetric examinations, specifically visible liquid dye penetrant (PT) examinations of both the outside (OD) surface and inside (ID) surface of each DM weld, and Phased-Array ultrasonic (UT) examination of the volume of each DM weld. The examination area and volume were to be the same as for a normal Inservice Inspection (ISI) examination of these welds.

EPRI contracted Structural Integrity Associates, Inc.(SIA) to perform the NDE, which also required a procedure expansion of the SIA phased-array UT procedure SI-UT-130.

Initial Visit to the Memphis Facility:

I first met with Kevin Butler and David Jennings, at the Studsvik/Race facility on Presidents Island in Memphis on January 25th, in order to look at the Pressurizer heads and to give the facility instructions on how to prepare the 6 associated dissimilar metal welds for examination. The as-found condition of the nozzles was that they were fully intact and in the same condition as they had come from the plant. The lower head piece contained one nozzle, which was the 14 Surge nozzle. This nozzle had a screen/filter associated with it, which was located on the inside surface of the head. The upper head piece contained five nozzles, which were the 3 Spray nozzle, the 4 Relief nozzle, and three 4 Safety nozzles. The Spray nozzle also had a nozzle associated with it on the opposite surface of the head, which had been internal to the Pressurizer during operation.

Each of the 6 nozzles appeared to have end caps welded on them, and the external surface of both head pieces appeared to be coated with some sort of paint or protective coating.

Upper Head Piece showing five nozzles and the internal portion of the Spray nozzle Cut line MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report Lower head containing the Surge nozzle Internal portion of Surge nozzle Cut line During the initial visit to the facility, I explained a little bit about the examinations that we were going to be performing on the nozzles and why. I requested that the two internal nozzles be cut off of the head pieces, and that each end cap be completely removed, so that we would have access to the ID of each nozzle. I instructed them to remove any internal thermal sleeves that would interfere with our access to the inside surfaces of the welds, as well. I also requested that all paint, coatings, rust and scale be removed from all surfaces of the pieces, down to the bare metal. At that time, they expressed concern for their ability to remove the end cap from the Surge nozzle, due to the size of the weld. We discussed that it should only involve cutting along the weld at the edge of the cap, and that the cap should come off fairly easily. They also asked me if it would be a problem if the flanges on the Safety nozzles were damaged during the cutting, and I said that it was not a concern as long as the weld area of the nozzle was not affected.

The February 4th Week at the Memphis Facility:

Upon arrival to the facility on Monday, February 4th, we received radiation worker training and facility safety training and were then allowed to dress out and enter the Sectional Shop, where the pieces were staged. The as-found condition of the upper head piece, at this time, was that the internal nozzle and end caps had been completely removed and the surfaces had been bead blasted with some sort of carbon steel metallic material, which had removed all paint and coatings but left the surface in a rough rusty looking condition. Even the stainless and inconel surfaces were rusty. Our assumption was that this was caused from carbon steel blast material being embedded into the surfaces. The flanges at the ends of the three Safety nozzles were completely removed along with the end caps. On the lower head piece, the DM weld on the Surge nozzle was actually damaged from the cutting and there were portions of the end plug still in place.

When I inquired about this, they told me that the end cap had actually been a plug and that it had been very difficult to remove. I took one of the facilities cutting technicians out to the nozzle and showed him the portions of the plug that were still in place and asked him to carefully remove the weld around the edge of it, and that it would come out.

He followed these instructions and was able to remove the remaining portion of the plug.

MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report An assessment of the Surge nozzle, after complete plug removal showed that a great deal of the ID of the weld had been damaged by flame cutting.

Upper Head after initial prep work Safety nozzle after flange removal Surge nozzle after initial prep work (note ID damage caused by flame cutting)

Portions of the end plug still in place Flame cut hole in the DM weld MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report We had brought our own side grinder and flapper wheels, so we proceeded to prepare the outside surfaces of the nozzle weld areas to remove the rust and smooth out the rough surfaces. By the end of the first day, we had managed to adequately prepare the outside surfaces of the welds for PT and UT examinations.

Upper head after flapping Surge nozzle after flapping and plug removal On Tuesday, we set up and performed liquid dye penetrant (PT) examinations of the OD surface of each DM welds. There were two small rounded indications noted during the OD PT exams. One was on the Relief nozzle, in the DM weld surface area. And the other was on the C Safety nozzle, also in the DM weld surface.

Relief Nozzle OD PT indication C Safety nozzle OD PT indication MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report Tuesday afternoon, we began Phased-Array UT examination on the A Safety nozzle DM weld, using longitudinal ultrasonic sound beams projected from 0° to 80° angles. We immediately noted a large number of planar reflectors in the weld, which were stacked on top of each other and appeared to extend from the ID surface of the weld up to approximately 0.325 from the OD surface of the weld, at the deepest point. These reflectors were numerous and were present 360° around the circumference of the weld.

When scanning across the tops of these indications, the UT sound beams that were projected normal to the surface (straight beams) did not pick up the indications, as you would expect them to if the indications were caused by internal inclusions. Under normal field examination conditions, these types of indications would have to be recorded and evaluated as one continuous linear planer flaw, seen 360° around the weld.

Screen shot of these stacked UT indications, as seen at the 3 oclock position Stacked indications Backwall On Wednesday, we continued UT examination of the remaining nozzles. The two other Safety nozzle DM welds also contained 360° linear planar indications. The B Safety DM weld indication was measured from the ID surface to within 0.396 of the outside surface. The C Safety nozzle DM weld indication was measured from the ID surface up to 0.495 of the outside surface. These indication exhibited the same features as that of the A Safety nozzle DM weld.

MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report The Spray nozzle DM weld was found to contain one embedded planar indication that did not appear to be connected to the ID surface, and was indicative of a lack of fusion type flaw located along the upper bevel of the weld to base material interface. The Relief and Surge nozzles did not contain any recordable indications.

Wednesday evening, we purchased a die grinder and some abrasive wheels in order to prepare the ID surfaces of these DM welds for PT examination. On Thursday, we were able to use these new tools to prepare a suitable ID surface for examination on each nozzle DM weld. The PT of the inside surfaces the A and C Safety nozzles produced several aligned dotted indications within the weld material, which were very defined and easy to interpret as surface connected flaws. The B Safety nozzle had three very faint indications in one area of the weld inside surface, which were reproducible, but were not as definitive as on the other two Safety nozzles. Surprisingly, the Spray and Surge nozzles also had recordable PT indications on the ID surfaces, in the area of the DM weld. They, too, were aligned. The Surge nozzle indications were somewhat small and faint, similar to that of the B safety nozzle. However, the Spray nozzle indications were very defined and sizeable. We re-examined the Surge and Spray nozzle DM welds after the ID PT examinations, but were still unable to record UT indications associated with the PT indications.

Typical Safety nozzle aligned ID PT indications Spray nozzle aligned ID PT indications MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report Faint ID PT indications on the Surge nozzle Summary of NDE findings:

All six nozzle DM welds on the former St. Lucie Combustion Engineering Pressurizer vessel were successfully examined from both the OD and ID with liquid dye penetrant, and were volumetrically examined by the Phased-Array UT method, using Structural Integrity Associates PDI qualified procedure SI-UT-130. The only limitations to these examinations were on the Surge nozzle, where initial attempts to remove the end plug by flame cutting had resulted in extensive damage to the ID surface and in one area had resulted in a hole through the middle of the DM weld.

The OD surface PT examinations of these six nozzle welds resulted in two recordable indications. One small rounded indication was recorded in the Relief nozzle DM weld crown surface. One small rounded indication was recorded in the C Safety nozzle DM weld crown surface. Both of these indications were indicative of porosity-type indications, which may have been uncovered during the bead blasting and flapping processes. Further surface preparations were not performed in the areas of these indications to see if they could be removed.

The phased-array UT examinations of the nozzles resulted in multiple stacked planar indications being recorded in all three of the Safety nozzle DM welds, which under normal field NDE conditions would likely be reported as 360° linear planar flaws. The approximate through-wall depths of these indications at the deepest points were 80% on the A Safety nozzle, 75% on the B Safety nozzle, and 69% on the C Safety nozzle.

Additionally, one non-surface connected indication, indicative of lack of fusion was MRP 2008-012

St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report recorded on the Spray nozzle. No recordable indications were noted on the Relief or Surge nozzles, during the UT examinations.

The ID surface PT examinations of the nozzles resulted in multiple, well defined, aligned surface indications being recorded in the weld root area of the A and C Safety nozzles and the Spray nozzle. The B Safety nozzle and Surge nozzle each showed a few faint indications in the weld root area, which were not as well defined, but were recordable. The Relief nozzle did not reveal any ID surface indications. As with the OD surface indications that were noted, all of these ID connected indications could have been uncovered during the surface preparation activities. Further surface preparations were not attempted in the areas of any of these ID indications to see if they could be removed.

Conclusions The two rounded indications recorded during the OD PT examinations are not unusual, during normal ISI surface examinations. Additional grinding would normally be prescribed to attempt to remove these indications. Surface Eddy Current examination could also be utilized to determine if these indications become linear underneath the surface.

The UT indications recorded on the three Safety nozzles contained multiple planar reflectors, which appear to be vertically stacked and extend from the ID surface to a significant through-wall depth. These indications are indicative of corrosion cracking, but could also be attributed to multiple stacked inclusions in the weld material, left over from construction. Performing automated UT on these three nozzle welds would allow for better flaw mapping and analysis. However, under normal field NDE conditions, these three welds would certainly be reported as containing 360° linear planar flaws of significant through-wall depth, which would require immediate repair.

The aligned ID PT indications noted on several of these nozzles could also be indicative of corrosion cracking. During many recent PT examinations of Reactor Upper Head penetration welds, PWSCC flaws were initially recorded as small aligned snake bite indications in the surface of the weld, which upon further surface grinding revealed linear cracking. However, it is also possible that the initial surface preparation of these welds uncovered inclusions in the weld material, which may have been removed upon further surface preparation. Surface Eddy Current examination could also be used to determine whether or not these indications are linked.

MRP 2008-012 MRP 2008-014

MRP Materials Reliability Program_________________________MRP 2008-014 (via email)

March 4, 2008 U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research Washington, DC 20555-0001 ATTN: Al Csontos and Bob Hardies

Reference:

MRP 2008-012 Examination Results on Nozzles from removed St Lucie Pressurizer with attachment St. Lucie Pressurizer Nozzle DM Weld Examination Project Internal Office Report

Dear Al and Bob:

As you know during our manual examinations of the St Lucie nozzles we did acquire some rough profile information on A pressurizer safety nozzle dissimilar metal weld circumferential indication. Please find attached the results of that effort. It should be noted, however, that this profile was created by taking 19 individual depth measurements and extrapolating a straight line in between them, which is not fully representative of what was noted during the actual field examination. In order to obtain a more accurate three-dimensional representation of the indication, or indications, it is recommended that an automated ultrasonic system be employed to take continuous measurements of the entire circumference of the weld. If you have any questions, please contact Craig Harrington (charrington@epri.com, 817-897-1433) or Ronnie Swain (rswain@epri.com, 704-595-2014).

Sincerely, Christine King Program Manager EPRI Materials Reliability Program

A Pressurizer Safety Nozzle Dissimilar Metal Weld Circumferential Indication Profile The graphic below represents a normalized side-view profile of the A Safety Nozzle DM Weld indication, based on ultrasonic depth measurements recorded at 1.0 inch increments around the circumference of the nozzle. The numbers, included below, represent the remaining ligament of material above the indication. The additional pages included with this graphic contain screen captures of each ultrasonic measurement location, as well as additional information that was used to derive the result.

The percentage of degraded material according to this graphic is estimated to be 64% of the total wall thickness. It should be noted, however, that this profile was created by taking 19 individual depth measurements and extrapolating a straight line in between them, which is not fully representative of what was noted during the actual field examination. In order to obtain a more accurate three-dimensional representation of the indication, or indications, it is recommended that an automated ultrasonic system be employed to take continuous measurements of the entire circumference of the weld.

MRP 2008-014

A Safety Circumferential Indication Profile Data Location: At the 0 stamp (circumferential reference point)

Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.38 inches Estimated remaining ligament above the indication: 0.32 inches Angle used for measurement: 67 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 1 inch clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.49 inches Estimated remaining ligament above the indication: 0.21 inches Angle used for measurement: 73 degrees MRP 2008-014

MRP 2008-014 A Safety Circumferential Indication Profile Data Location: 2 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.39 inches Estimated remaining ligament above the indication: 0.31 inches Angle used for measurement: 66 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 3 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.51 inches Estimated remaining ligament above the indication: 0.19 inches Angle used for measurement: 79 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 4 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 0.79 inches Estimated remaining ligament above the indication: 0.91 inches Angle used for measurement: 37 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 5 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.17 inches Estimated remaining ligament above the indication: 0.53 inches Angle used for measurement: 65 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 6 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.31 inches Estimated remaining ligament above the indication: 0.39 inches Angle used for measurement: 70 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 7 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 0.9 inches Estimated remaining ligament above the indication: 0.80 inches Angle used for measurement: 53 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 8 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.34 inches Estimated remaining ligament above the indication: 0.36 inches Angle used for measurement: 66 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 9 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.19 inches Estimated remaining ligament above the indication: 0.51 inches Angle used for measurement: 54 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 10 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 0.71 inches Estimated remaining ligament above the indication: 0.99 inches Angle used for measurement: 60 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 11 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.27 inches Estimated remaining ligament above the indication: 0.43 inches Angle used for measurement: 49 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 12 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.43 inches Estimated remaining ligament above the indication: 0.27 inches Angle used for measurement: 67 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 13 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.48 inches Estimated remaining ligament above the indication: 0.22 inches Angle used for measurement: 70 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 14 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 0.99 inches Estimated remaining ligament above the indication: 0.71 inches Angle used for measurement: 40 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 15 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.23 inches Estimated remaining ligament above the indication: 0.47 inches Angle used for measurement: 67 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 16 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.17 inches Estimated remaining ligament above the indication: 0.53 inches Angle used for measurement: 69 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 17 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.41 inches Estimated remaining ligament above the indication: 0.29 inches Angle used for measurement: 65 degrees MRP 2008-014

A Safety Circumferential Indication Profile Data Location: 18 inches clockwise from 0 stamp Part Thickness used for calculation: 1.7 inches Indication through-wall depth at this location: 1.47 inches Estimated remaining ligament above the indication: 0.23 inches Angle used for measurement: 74 degrees MRP 2008-014 UT Report

MARCH 15, 2008 REPORT

SUMMARY

PSL FIELD REMOVED PRESSURIZER SAFETY NOZZLE TO FLANGE DISSIMILAR METAL WELDS During the week of March 9th, 2008; LMT was requested to examine three Pressurizer Safety Nozzle to Flange Welds utilizing The Procedure for Encoded, Manually Driven, Phased Array Ultrasonic Examination of Dissimilar Metal Piping Welds; Zetec_OmniScanPA_03; Revision D; Addenda: 0. Variations to the procedure were required due to the unique configuration of the Port St. Lucie nozzles. The variations were successfully demonstrated to the EPRI Performance Demonstration Administrator in accordance with the ASME Boiler and Pressure Vessel Code,Section XI, Appendix VIII, Supplement 10. A formal Technical Justification documenting the demonstration was not complete at the time of this report but is forth coming.

The three safety nozzles were identified as A, B, and C. The examination result for each nozzle is described below:

PSL Safety Nozzle A (Reference Report EPRI-PA-01)

Nine indications attributed to subsurface flaws resulting from the fabrication process were recorded. These flaws were characterized as embedded flaws that lie wholly beneath and are adequately separated from the ID / OD surface of the component.

PSL Safety Nozzle B (Reference Report EPRI-PA-02)

Five indications attributed to subsurface flaws resulting from the fabrication process were recorded. These flaws were characterized as embedded flaws that lie wholly beneath and are adequately separated from the ID / OD surface of the component.

PSL Safety Nozzle C (Reference Report EPRI-PA-03)

Seven indications attributed to subsurface flaws resulting from the fabrication process were recorded. These flaws were characterized as embedded flaws that lie wholly beneath and are adequately separated from the ID / OD surface of the component.

It should be noted that examinations were performed in the axial scan direction only by customer request as an aid to better resolve circumferential indications recorded with manual Phased Array techniques.

It should also be noted that flaw characterization and sizing methods utilized are qualified methods for surface connected planar flaws only. The full amplitude drop method was used to dimension these embedded flaws as it was felt to be the most conservative approach. Due to the severity of the possible industry implications concerning these particular welds, LMT felt that this approach was the appropriate one to take.

Jeff Devers General Manager LMT, Inc.

Figure 1 PSL Safety Nozzle 'A' Looking Into Head Figure 2 PSL Safety Nozzle 'A' Looking Away from Head Figure 3 PSL Safety Nozzle 'B' Looking Into Head Figure 4 PSL Safety Nozzle 'B' Looking Away from Head Figure 5 PSL Safety Nozzle 'C' Looking Into Head Figure 6 PSL Safety Nozzle 'C' Looking Away from Head

Attachment 4 Technical Justification for the Acceptance of Ultrasonic Examination Demonstration Results on Port St. Lucie Pressurizer Safety Nozzle Dissimilar Metal Weld Mockup iii

3/13/2008 Timothy OHara Region I 475 Allendale Road King of Prussia, PA 19406

Subject:

PDI Qualification Changes to PDI Qualified Procedure ZETEC-OMNISCAN-PA03 Revision D

Dear Mr. OHara:

The purpose of this letter is to document the qualification activities performed at the Studsvik facility in Memphis, Tennessee on March 12, 2008. This demonstration was performed to qualify an additional search unit wedge that was used to examine safety nozzles A, B and C on the pressurizer that had been removed from service in Port St.

Lucie (PSL), Unit 1.

The PSL nozzles were examined using a search unit/wedge combination that was contoured for a larger component diameter, because the standard kit of wedges for this procedure does not include a wedge that is contoured ideally for the PSL safety nozzle diameter. This application of a larger-diameter wedge contour had not implemented during the original qualification of the procedure. The performance of this larger-diameter wedge was evaluated by comparing the examination data from the PSL safety nozzle welds against data collected during the original qualification of the procedure. This evaluation concluded that the overall quality of the data was comparable.

In addition, the procedure was demonstrated using the larger-diameter wedge on a mockup that is fully compliant with the quality and design standards of the Performance Demonstration Initiative (PDI), matches the exact configuration of the PSL safety nozzles, and contains cracks. The demonstration was performed in accordance with PDIs implementation of ASME Boiler and Pressure Vessel Code,Section XI, Appendix VIII, Supplement 10. The data was of high quality, the reported results satisfied the acceptance criteria defined in Appendix VIII for detection, length and depth sizing, and no limitations were noted. Due to PDI data security requirements, the mockup flaw truth information cannot be included in this letter. EPRI will develop a formal technical justification in the next several days to formally document this demonstration, but until this is completed and reviewed internally this letter should be used as an attestation that the equipment and techniques were qualified in full compliance with the PDI program.

Sincerely, Carl Latiolais EPRI Program Manager Appendix VIII Performance Demonstration c: G. Selby T. MaCalister (SCANA)

ABSTRACT Neither ASME Section XI [1], nor the Performance Demonstration Initiative (PDI) Program, requires that an Appendix VIII Supplement 10 (Dissimilar Metal Piping Weld) qualification test set include all possible configurations. The intent of the PDI Program is to perform a thorough and complete examination on all dissimilar metal piping weld configurations. However, due to the numerous different configurations present in the industry, it is not feasible for the PDI Program to include all of them in a single qualification test. Therefore, qualified procedures for the examination of dissimilar metal piping welds may require the use of an additional mockup or mockups when the component configuration contains variations that were not included in the procedure qualification. Mockups are used to optimize the essential inspection variables and to demonstrate the effectiveness of the examination for that specific geometry. Essential inspection variables which may be revised include:

• Alternate search unit angles

• Size, focal depths and contours of the search units

• Selection of compound angles to accommodate tapered inspection surfaces

• Adjustment to scan patterns

• Other essential inspection variables as required These additional mockups also serve to aid examination personnel in familiarizing themselves with the ultrasonic responses from unique geometric configurations.

v

CONTENTS 1 INTRODUCTION ....................................................................................................................1-1 2 BACKGROUND / HISTORY / APPROACH ...........................................................................2-1 3 COMPONENT REQUIRING PROCEDURE MODIFICATION ................................................3-1 4 BASIS OF EXPANSION.........................................................................................................4-1 5 REQUIRED DEVIATIONS TO THE QUALIFIED TECHNIQUES DEFINED IN ZETEC_OMNISCAN_PA03.......................................................................................................5-1 6 CONFORMANCE TO DISSIMILAR METAL WELD MOCKUP CRITERIA, REVISION A .6-1 7 ASSESSMENT OF COVERAGE............................................................................................7-3 8 EQUIPMENT CHANGES FROM ZETEC_OMNISCAN_PA03...............................................8-1 9 EMPIRICAL DOCUMENTATION OF CHANGES ..................................................................9-1 Examination Limitations .......................................................................................................9-1 Port St. Lucie Safety Relief Mockup ASME Code Coverage Analysis.................................9-1 Search Unit Information .......................................................................................................9-2 10

SUMMARY

OF RESULTS..................................................................................................10-1 11 DEMONSTRATION DOCUMENTATION ...........................................................................11-1 12 REFERENCES ...................................................................................................................12-1 A SEARCH UNIT PARAMETERS/CERTIFICATES..................................................................... 2 B DEMONSTRATION DOCUMENTATION.................................................................................. 3 Flaw Prints .............................................................................. Error! Bookmark not defined.

vii

LIST OF FIGURES Figure 3-1 Weld Profile of the Port St. Lucie Safety Mockup.....................................................................3-1 Figure 7-1 Port St. Lucie Safety Nozzle Mockup - Looking Down-Stream Ultrasonic Beam Plot ............7-3 Figure 7-2 Port St. Lucie Safety Nozzle Mockup - Looking Up-Stream Ultrasonic Beam Plot .................7-4 Figure 7-3 Port St. Lucie Safety Nozzle Mockup - Ultrasonic Coverage ...................................................7-4 ix

LIST OF TABLES Table 5-1 Table of Deviations ....................................................................................................................5-1 Table 6-1 Dissimilar Metal Weld Mockup Criteria ......................................................................................6-1 Table 9-1 Wedge/Array Information...........................................................................................................9-2 xi

1 INTRODUCTION Neither ASME Section XI [1], nor the Performance Demonstration Initiative (PDI) Program, requires that an Appendix VIII Supplement 10 (Dissimilar Metal Piping Weld) qualification test set include all possible configurations. The intent of the PDI Program is to perform a thorough and complete examination on all dissimilar metal piping weld configurations. However, due to the numerous different configurations present in the industry, it is not feasible for the PDI Program to include all of them in a single qualification test. Therefore, qualified procedures for the examination of dissimilar metal piping welds may require the use of an additional mockup or mockups when the component configuration contains variations that were not included in the procedure qualification. Additional PDI mockups are used to optimize the essential inspection variables and to demonstrate the effectiveness of the examination for that specific geometry.

Essential inspection variables which may be revised include:

• Alternate search unit angles

• Size, focal depths and contours of the search units

• Selection of compound angles to accommodate tapered inspection surfaces

• Adjustment to scan patterns

• Other essential inspection variables as required These additional mockups also serve to aid examination personnel in familiarizing themselves with the ultrasonic responses from unique geometric configurations.

1-1

2 BACKGROUND / HISTORY / APPROACH When the pressurizer at Port St. Lucie (PSL) Unit 1 was replaced several of the nozzles were removed and saved for evaluation at a later date. Among the nozzles saved were three safety nozzle to flange dissimilar metal welds (DMW). The PSL pressurizer nozzles had never been examined using Performance Demonstration Initiative (PDI)-qualified UT techniques while they were in service. Therefore, the Nuclear Regulatory Commission Office of Nuclear Regulatory Research (NRC RES) and the Materials Reliability Program (MRP) engaged a nondestructive evaluation (NDE) vendor to examine the nozzles and learn which DMWs would be of greatest interest for the research program. This examination took place February 5-7, 2008 at the Studsvik Memphis facility where the nozzles were being stored. The examination vendor used a PDI-qualified manual phased array ultrasonic examination (UT) procedure to perform the examinations. The examiners preliminary conclusions were that all three safety nozzle DMWs contained indications of circumferential cracking around the entire circumference. The reported cracking was most severe in nozzle A. The examiner noted that the indications also could be consistent with stacked fabrication defects instead of cracking, and recommended that encoded ultrasonic examination should be performed in order to make a more precise interpretation. A dye penetrant examination (PT) of the inside surface of the nozzles resulted in a few, short linear indications, but nothing approaching the extent of the UT indications.

An additional NDE vendor company, Lambert MacGill and Thomas (LMT), was engaged to perform an encoded UT examination. LMT used the PDI-qualified procedure Procedure for Encoded, Manually Driven, Phased Array Ultrasonic Examination of Dissimilar Metal Piping Welds; Zetec_OmniScanPA_03; Revision D; Addenda: 0 [3]. This procedure uses a standard set of wedges contoured for various nozzle diameters. The PSL safety nozzles are of an unusual configuration and none of the available wedge contours were within the qualified range of the procedure. Therefore, the nozzles were scanned using the most appropriate of the available wedges, and the procedures qualification was expanded by demonstrating the effectiveness of the wedge in a blind test using a PDI-approved mockup of the same configuration. In addition, two additional angles were added to examination technique to help obtain additional coverage and aid in depth sizing of the deeper flaws reported during the previous examination.

The procedure employs a phased array probe with dual 2x16-element arrays mounted on a wedge with a 6° roof angle. The probe uses an 8-element virtual aperture to generate longitudinal-wave beam angles of 30°, 45°, 60°, and 70°. At each probe position the virtual aperture is scanned electronically through the 16-element actual aperture. The probe is manipulated manually as its position is tracked and recorded by an encoder system. The acquired data was analyzed off-line using Zetecs UltraVision software, version 1.1Q5. This software allows the analyst to view three-dimensional reconstructions of the ultrasonic data and to view slices and projections in three orthogonal planes.

2-1

This demonstration included only axial scans in an effort to address the safety significant circumferential flaws reported using manual phased array techniques. In order to address this and similar configurations not contained within the program, PDI has developed a set of guidelines and created the PDI Dissimilar Metal Weld Mockup Criteria, Revision A [2]. This document focuses on the key points that need to be addressed when modifying a qualified procedure for examinations performed on configurations not present in the procedure qualification. It requires the fabrication of a mockup to replicate the effects of the geometries not contained within the scope of qualified procedures.

This report describes the process and basis for the modification of Zetec_Omniscan-PA03.

Ultrasonic beam plots of various discrete angles were used to address Port St. Lucies unique DMW configuration. The beam plots were used to select the optimum focal law angles and estimate the resulting coverage percentages. The approaches used in this project for array and wedge selection have proven to provide effective examinations of this and similarly configured components. The modifications to the procedure, necessary to address this component, will be included in a later revision to the procedures Performance Demonstration Qualification Summary (PDQS).

The objective of this project was to evaluate the detection, length sizing, and depth sizing capabilities of the technique and the modifications necessary to compensate for the unique geometries associated with the PSL safety nozzles.

A mockup owned by FPL Energy was used for this demonstration activity. The mockup accurately represents the PSL pressurizer safety nozzle with respect to material and form.

Section 6 of this report addresses in detail how this mockup conforms to the requirements of the PDI Dissimilar Metal Weld Mockup Criteria, Revision A. While these criteria do not require the testing to be performed in a blind fashion, the data analysis portion of this demonstration was performed by an analyst that had no prior knowledge of the number, size and location of the flaws in the mock-up.

2-2

3 COMPONENT REQUIRING PROCEDURE MODIFICATION This technical justification (TJ) is applicable to the first welds off of the safety nozzles located on top of the pressurizer. The materials and DMW configuration for the manufactured mockup is as indicated in Figure 3-1. Review of the Westinghouse supplied fabrication drawing for the PSL Unit 1 safety nozzles confirmed that mock-up matched the actual field removed components. The direction of flow indicated in Figure 3-1 may differ than that of the actual field installed component. All scan direction references in this report are based on the mockup and not the actual component.

Port St. Lucie Safety Nozzle to Flange Site Specific Mockup Weld Profile 1.500" DNST R0.750" 0.250" 15° 4.057" UPST 0.219" 1.250" R0.313" 7.247" 4.810"

Ø7.688" Ø6.063"

Ø2.938" INCO 304 SS CLAD 182 NOZZLE SA-105 GR. 2 INCO SAFE END (CARBON STEEL) 182/82 316 SS Figure 3-1 Weld Profile of the Port St. Lucie Safety Mockup 3-1

4 BASIS OF EXPANSION The PDI DMW qualification program does not contain samples in the thickness range that address the specific weld configuration associated with the PSL safety nozzles. Because the procedure did not include a wedge/array combination to inspect components between six and eight inches, it was necessary to demonstrate the procedure modifications on a PDI designed mockup. Using beam simulation software for phased array search units, it was established that by adding a 30° focal law to the scan plan it would add coverage by an additional angle as well as increase the flaw resolution. In addition, because of the number of and type of flaws previously reported in the prior examination a 70° focal law was added to the examination plan in order to provide better depth sizing capability for the deeper flaws reported.

4-1

5 REQUIRED DEVIATIONS TO THE QUALIFIED TECHNIQUES DEFINED IN ZETEC_OMNISCAN_PA03 Table 5-1 below details the procedure deviations required to adjust for the unique configuration of Port St. Lucie Safety Nozzle-to-Flange components. Only areas within the procedure that require modification are listed in Table 5-1. The primary reason for the deviation from the procedure is that there were no appropriate wedge/array combinations qualified for use on components between six and eight inches. Furthermore, adding the 30° focal law to the scan plan allowed the search unit to be focused closer to the inside surface while providing additional coverage with a supplementary angle. A 70° focal law was added in order to assist with depth sizing of the deeper flaws reported by the previous examination.

Table 5-1 Table of Deviations Procedure Deviations Alternative Techniques/Comments Paragraph The procedure does not specify a The wedge/array combination specified for use on wedge/array combination for longitudinal components between 8 and 12 inches will be used to 5.4.3 wave or transverse wave inspections on address the Port St. Lucie safety nozzle to flange DM components between 6 and 8 inches. welds.

The procedure only requires the use of a For the exam of the Port St. Lucie safety nozzles the 30 30 degree longitudinal wve focal law 5.5.1 degree longitudinal wave focal law was used in both of when scan limitations are present on the the looking-up and looking-down exams.

nozzle side.

The procedure does not require the use of In order to accurately size indications, from the nozzle a 70 degree longitudinal wave focal law side, that extends into the upper portion of the volume it 5.5.1 when scanning on the nozzle side of the would be necessary to add the 70 degree focal law for weld. both scan directions.

The merges specified within the When the additional focal laws are used they will be procedure do not include the 30 and 70 9.3.2 merged separately as well as included in the all angle degree angles added to address this merge.

component.

5-1

6 CONFORMANCE TO DISSIMILAR METAL WELD MOCKUP CRITERIA, REVISION A The purpose of Table 6-1 is to identify how the site-specific mockup complies with the requirements of Section 4 of the Dissimilar Metal Weld Site Specific Mockup Criteria, Revision A.[2]

Table 6-1 Dissimilar Metal Weld Mockup Criteria Criteria Complied Paragraph Means of Compliance w/Criteria Requirement 4.1 Yes The original procedure qualification did not contain PDI samples representative of Port St. Lucie safety nozzle components. The site-specific mockup was built to represent the actual in-service components.

The mockups address the limited scan access due to the nozzle and flange location.

4.2.1 Yes Material types and product forms are presumed to be identical to the removed component.

4.2.2 Yes The mockup was manufactured using similar welding techniques to those used when manufacturing the Port St. Lucie safety nozzle to flange components.

4.2.3 Yes The Port St. Lucie safety nozzle to flange component does not contain a taper.

4.2.4 Yes All physical limitations are present or simulated.

4.2.5 Yes All inside surface geometric conditions warranting duplication were represented in the mockup.

4.2.6 a) thru j) Yes The flaws contained within the mockup were manufactured in accordance with the PDI fabrication quality program.

4.2.7 a) thru d) N/A This mockup was not commercially dedicated.

4.3 Yes A sufficient number of flaws were placed in the mockups taking into consideration the component geometry and scan limitations.

4.4 Yes All flaws are in conformance with the PDI Dissimilar Metal Weld Mockup Criteria, Revision A.[2] No flaws exceeded 20% of the nominal wall thickness.

4.5 Yes All flaws in this mockup were produced via the thermal fatigue or alternative flaw processes and compressed using the hot isostatic pressure (HIP) process to ensure a final flaw tip width of less than or equal to 0.002 inch (0.05mm). The alternate flaws were fabricated to have crack-like characteristics.

4.6 Yes The mockup contains flaws oriented in both the axial and circumferential directions in areas known to be susceptible to cracking. All flaws in the mockup were placed in the weld material or heat-affected zones with 6-1

emphasis placed on the weld and butter materials.

6-2

7 ASSESSMENT OF COVERAGE Figures below depict the expected examination volume coverage obtained using the techniques in this document. The extent of scanning is limited by the search unit size and the proximity of the nozzle blend and the flange. Axial scans looking in both directions were performed from the base material and extended across the weld and onto the nozzle as well as the flange. No physical limitations were noted that would interfere with obtaining the procedurally defined coverage. Obtainable coverage will vary based on each of the field removed components unique contour. See Examination Limitations in Section 9 of this report for ASME code exam volume coverage details for the Port St. Lucie safety nozzle mockup.

Port St. Lucie Safety Nozzle to Flange Site Specific Mockup Looking Down-Stream UT Beam Plot 30 30 45 45 60 60 70 70 Figure 7-1 Port St. Lucie Safety Nozzle Mockup - Looking Down-Stream Ultrasonic Beam Plot 7-3

Port St. Lucie Safety Nozzle to Flange Site Specific Mockup Looking Up-Stream UT Beam Plot 30 30 45 45 60 60 70 70 Figure 7-2 Port St. Lucie Safety Nozzle Mockup - Looking Up-Stream Ultrasonic Beam Plot In Figure 7-3, the heavy red (bold) line indicates where coverage could be claimed using the techniques and examination volume defined within the procedure.

Port St. Lucie Safety Nozzle to Flange Site Specific Mockup Coverage Plot 30 30 30 30 45 45 45 45 60 60 60 60 70 70 70 70 Figure 7-3 Port St. Lucie Safety Nozzle Mockup - Ultrasonic Coverage 7-4

8 EQUIPMENT CHANGES FROM ZETEC_OMNISCAN_PA03 The PDI Dissimilar Metal Weld Site Specific Mockup Criteria, Revision A[2] allows for technique adjustments to a qualified procedure to compensate for component geometries that were not included in the procedure qualification. These technique adjustments are limited to search unit parameters such as angle, focusing, and contouring. In addition to search unit parameters, adjustments to the scan pattern may be made as well.

No procedural equipment deviations were required to perform the axial scans on the Port St.

Lucie safety nozzle mockup.

8-1

9 EMPIRICAL DOCUMENTATION OF CHANGES See Attachment B for the on-site demonstration ultrasonic examination documentation. The flaws contained within the mockups were readily detectable and had a signal to noise ratio that was 2:1 or greater during the on-site performance demonstration. All flaws were sized within the acceptance criteria of ASME Section XI, Appendix VIII, Supplement 10 [1].

Examination Limitations See Coverage Plots, Section 7, for a pictorial representation of the estimated coverage obtainable. Examination volume coverage percentages in this report are based on the configuration and surface condition of the provided mockup and the actual mock-up. The calculated examination coverage presented in this report is based on simple geometric renditions of the ultrasonic beams using straight lines for the discrete angles generated by the phased array search unit. It should be noted that there is not yet a consensus in the industry on how to determine examination coverage or how to introduce the relative effectiveness of individual scans in a composite coverage figure. The examination volume coverage calculations here are based on AutoCAD models and may differ from those calculated by physical measurements.

Port St. Lucie Safety Nozzle Mockup ASME Code Coverage Analysis The axial scan coverage for the Safety Relief, nozzle to flange dissimilar metal weld mockup, where two angles passed through the examination volume, is 100%.

Port St. Lucie Safety Nozzle to Flange Site Specific Mockup ASME Code Exam Volume Coverage Plot 60 45 60 45 60 45 60 9-1

Search Unit Information The parameters for the actual array wedge combination used for this demonstration and for the actual examination are shown in Table 9-1 below. For additional information pertaining to the array/wedge combinations, see Attachment A.

Table 9-1 Wedge/Array Information Flaw Config., Probe Probe Contour Assembly Manuf. Wedge Roof Type Type Position, model angle angle Wave mode Skew T/R Nozzle, 90º CIRC CS 12 ADUXE039A Zetec 22.3º 6.0º Long., Shear Pipe, 270º 9-2

10

SUMMARY

OF RESULTS The PSL safety nozzle DMW configuration was not represented within the PDI Program sample inventory at the time procedure Zetec_OmniScanPA_03; Revision D; Addenda: 0 was qualified. Due to the unique configuration of these welds, the qualified array/wedge combination defined within the procedure required modifications. The primary reason for the deviation from the procedure is that there were no appropriate wedge/array combinations qualified for use on components between six and eight inches. Furthermore, by adding the 30° focal law to the scan plan will allow the search unit to be focused closer to the inside surface while providing additional coverage with a supplementary angle. A 70° focal law was added in order to assist with depth sizing of the deeper flaws reported by the previous examination.

All modifications to the previously qualified procedure can be found in Table 5.1 of this document.

The PDI Dissimilar Metal Weld Mockup Criteria, Revision A was followed for the flaw design, flaw fabrication, and examination demonstration for PSL safety nozzle mockup. The mockup was designed and built to accurately represent the in-service components. The diameter and thickness combination provided challenges to proper search unit selection. These challenges were offset by evaluating the effective beam formation using an advanced beam simulator, selecting the most appropriate array/wedge combination and successfully demonstrating it on a representative mockup.

The search units and techniques outlined in this technical justification yield adequate mockup examination volume coverage and detection capabilities for circumferential flaws. Axial scan coverage with all angles, excluding the 70° beam which was used for sizing only, is 100%. No circumferential scanning was performed during this demonstration.

All flaws that were implanted into the mockups were successfully detected at signal-to-noise ratios of 2:1 or greater.

The depth and length sizing techniques defined in procedure Zetec_OmniScanPA_03; Revision D; Addenda: 0 were used during the demonstration and the reported values were well within the acceptance standards defined in ASME Section XI, Appendix VIII, Supplement 10 [1].

The documentation of the on-site demonstration showing the calibration and indication data sheets with amplitude measurements is attached to this document as Attachment B.

10-1

11 DEMONSTRATION DOCUMENTATION See Attachment B.

The demonstration grading sheet is included as Attachment C.

11-1

11-1

12 REFERENCES

1. ASME Section XI, Appendix VIII.

2. PDI, Dissimilar Metal Weld Mockup Criteria, Revision A.

3. Procedure for Encoded, Manually Driven, Phased Array Ultrasonic Examination of Dissimilar Metal Piping Welds; Zetec_OmniScanPA_03 Rev. D Addenda 0 12-1